In #3803 the NppStreamHandler was added for the nppiEvenLevelsHost_32s due to the documentation having a streaming version (_Ctx see https://docs.nvidia.com/cuda/archive/11.0/npp/group__image__histogrameven.html#ga1586db7ec07d9a7b5929b981e99676e0). I have since found out that this is a host-only function and the header for the streaming version will be removed in the next version of CUDA so unnecessary delay from the call to NppStreamHandler can be removed.

Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

• I agree to contribute to the project under Apache 2 License.
• To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
• The PR is proposed to the proper branch
• There is a reference to the original bug report and related work
• There is accuracy test, performance test and test data in opencv_extra repository, if applicable
  Patch to opencv_extra has the same branch name.
• The feature is well documented and sample code can be built with the project CMake